Digital Light Processing (DLP) is one of the major additive creation technologies. It is a type of vat polymerization, similar to stereolithography, where a light source is used to cure a liquid photopolymer resin into specific shapes.
In the case of DLP, the light source is usually a digital UV light projector. (Stereolithography often uses a UV laser beam.) The benefit of the UV light projector is that it can cover more area in one pass than traditional stereolithography, making the build process fast. DLP exposes one cross-section of material, speeding the curing/building process.
The DLP process exposes light in pixels. The brightness of these pixels can be controlled individually, enabling different depths of curing, which enable greater accuracy and surface finish.
The vendors that use DLP technology, however, have developed some refinements to it to further speed up a build. Here’s a look.
Chuck Hull of 3D Systems invented stereolithography. And he was instrumental in creating the Figure 4, which uses a DLP process. Figure 4 uses a non-contact membrane Digital Light Printing (DLP) unit for the production of plastic parts. The system can print at 100 mm per hour at six sigma repeatability.
B9Creations uses a more traditional DLP unit for its 3D printers–an industrial HD UV LED Light Engine. The B9 Core Series is an example. The printer can reach print speeds of 100+ mm per hour
Carbon offers Digital Light Synthesis technology. The company’s efforts helped ignite the race to turn vat photopolymerization into a faster technology. This innovation sped up the build process considerably. Carbon researchers found a way to inject oxygen into the resin at a precise point in the build to inhibit the resin from curing too quickly.
EnvisionTEC was one of the first 3D printing vendors to use DLP technology and has since introduced variations of it to speed the build process even more. Continuous Digital Light Manufacturing (CDLM) is one variation. The build plate undergoes continuous motion in the Z direction for faster build speeds. EnvisionTEC also offers 3SP (Scan, Spin, and Selectively Photocure), a technology that uses a UV laser to rapidly scan, spin and selectively photocure a variety of resins.
Prodways offers its patented DLP MOVINGLight technology in its LD and L Series 3D printers. MOVINGLight DLP is a photopolymerization process that polymerizes photosensitive resins with moving DLP (Digital Light Processing) UV rays. Prodways is contrasting this to “fixed” DLP which projects one image over the entire surface of the resin container. Moving DLP can project a 40 x 70 mm image made up of 2 million pixels that sweeps across the entire surface of polymer resin. The result of this moving approach is a resolution of 40 microns per pixel on every part of the build platform.